Fin wrapping machine for heat exchanger tubes



sept. 1 8, 1956 W. F. MATHENY FIN WRAPPING MACHINE FOR HEAT EXCHANGER TUBES Filed March 25. 195;

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VENTOR wlLuAM F. MTTHENY ATTORNEY FIN WRAFPING MACHINE FOR HEAT EXCHANGER TUBES Filed March 25, 1953 3 Sheets-Sheet 2 fr un N 1 1Q v 'A INVENTOR w "x TWD 'HD w|LuAM F. MATHENY ATTORNEY Sept. 18, 1956 w. F. MATHENY 2,763,364

FINWRAPPING MACHINE FOR HEAT EXCHANGER TUBES Filed March 25. 1955 3 Sheets-Sheet 3 FIG.7.

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INVENTOR WILLIAM F. MATHENY ATTORNEY FIN WRAPPIN G MACHINE FOR HEAT EXCHANGER TUBES William F. Matheny, Tulsa, Okla.

Application March 23, 1953, Serial No. 343,944

1 Claim. (Cl. 203-75) This invention consists in new and useful improvements in a iin wrapping machine for use in the manufacture of heat exchanger tubes of the type wherein a helical fin strip is wound upon the periphery of a tube. In a separate copending application, Serial No. 318,018, tiled October 31, 1952, and now Patent No. 2,692,004, l have illustrated and described a mechanism for crimping metal strips to condition them for being helically wound on a tube, said mechanism being designed to apply a series of base crimps along one edge of a strip of metal to serve as the supporting edge of the helically wound strip. The other edge of the strip is crimped in a manner Which actually deforms and stretches the strip by flattening its edge between a series of cooperating dies which facilities lthe helical winding of the strip in the 1in Wrapping operation.

It is the object of the present invention to provide a fin wrapping mechanism which receives the crimped strip, fed from the machine of my said copending application and winds the same on a progressively advancing and rotating tube while guiding the strip in a helical path of a predetermined pitch.

Still another object of the invention resides in the provision of a novel tube controlling mechanism adapted to simultaneously rotate the tube and advance the same longitudinally through the iin-wrapping unit.

With the above and other objects in view which will appear as the description proceeds, my invention consists in the novel features herein set forth, illustrated in the accompanying drawings and more particularly pointed out in the appended claim.

Referring to the drawing in which numerals of like character designate similar parts throughout the several views,

Figure 1 is a view in side elevation, showing the relationship of the tube-rotating and advancing unit and the cooperating iin Wrapping unit.

Figure 2 is a transverse sectional View taken on line 2-2 of Figure 1, showing the xed gear of the system which controls the operation ofthe feed rolls of the tube advancing and rotating mechanism.l

Figure 3 is a top plan View of the mechanism4 shown in Figure 1.

Figure 4 is a sectional View taken on line 4 4 of Figure 3, showing the planetary gear system.

Figure 5 is an end view of the fin-flattening andv Wrapping unit, looking from the left in Figure 1.

Figure 6 is a diagrammatic view showing the progressively advanced relationship of the individual sheaves of the tube-flattening and wrapping unit.

Figure 7 is an enlarged Vsectional View showing the mounting means for one of the tin-flattening and guiding sheaves.

Figure 8 is a fragmentary View showing a section of the precrimped strip which forms the fin, and

Figure 9 is a fragmentary perspective view showing the iin Wrapped upon the tube.

v In the drawings, 10 represents the base ofthe machine,

. United States Patent Patented sept. 1s, 1956 having at opposite ends thereof, a pair of vertical supporting channels 11 and 12. As seen in Figures 1 and 3, the supports 11 and 12 are transversely drilled and provided with bearings 13 and 14 respectively, for rotatably supporting the tube advancing and rotating unit, generally indicated by the numeral 15.

This unit 15 consists of two coaxial circular end plates 16 and 17, connected in spaced relation by longitudinally extending, laterally spaced roller beds 18 and 19, each preferably formed of a pair of parallel angles. One end of each bed angle is welded or otherwise attached directly to the end plate 16, while the opposite ends of the angles of beds 18 and 19 are joined by intermediate transverse struts 20 and 20A which in turn are respectively attached to the end plate 17, by individual platforms 21 and 21A and supporting brackets 22 and 22A. These platforms and brackets are arranged on opposite sides of the unit 15, as Will be seen from Figure l.

Referring to Figures 2 and 3, the bearings 13 and 14 on supports 11 and 12, are adapted to embrace short hollow shafts 23 and 24 respectively. The shaft 23 carries a sprocket 25 for connection by chain 26, to any suitable source of motive power, generally indicated at 27. The shaft 23 extends through the bearing 13 Where it is welded or otherwise connected to the end plate 16, thus causing rotation of the entire unit 15, upon rotation of the sprocket 25. The opposite hollow shaft 24 is embraced by bearing 14 and is fixed at its inner end to the end plate 17, thus rotatably supporting the opposite end of the rotating unit 15.

The hollow shafts 23, 24 are concentrically arranged to' slidably receive the tube T and the mechanism for controlling the advance and rotation of the tube consists of a pair of opposed feeding rolls 28 and 29 mounted respectively between the angles of beds 18 and 19. Suitable bearing brackets 30, carrying cross shafts 31, are bolted to opposite faces of the beds 18 and 19, to rotatably support the rolls 28 and 29, so that their peripheries lie in opposed relation adjacent the tube T. These rolls are peripherally grooved to iit the contour of the tube T and engage the latter with suflicient pressure to rotate the tube upon rotation of the unit 15 and to simultaneously advance the tube upon rotation of the rolls 28 and 29, as as will hereinafter appear.

It will be noted that in order to insure firm gripping of the tube for rotation thereof, a pair of supplemental gripping rolls 32 and 33 are provided on beds 18, 19, respectively, adjacent the end plates 16. These rolls are smaller than rolls 28 and 29 and are freely mounted to rotate in suitable bearings 34 on cross shafts 35. They are also peripherally grooved to accommodate the tube T, and are positioned so as to firmly engage the tube, but to insure the firmness of gripping it is desirable to provide adjustable tension bolts 36, extending between the angles of opposed beds 18 and 19. Upon tightening the bolts 36 the angles of the beds 18 and 19 are slightly flexed to move the axes of the rolls 32 and 33 toward one another a sufficient distance, usually only a fraction of an inch, to increase the frictional engagement of their opposed peripheries on the tube.

The shafts of feeding rolls 28 and 29 are respectively provided with sprockets 37 and 38 which are connected by chain drives to reduction gear systems 39 and 40, said systems being oppositely supported on platforms 21 and 21A, respectively. The input shaft 41 of gear box 39 extends through plate 17 and is connected to a planetary gear 42. The input shaft 43 of gear box 4) also exf 42 and 44 in the usual manner. As shown in Figure 2, the hollow shaft 24 extends through a central opening in the fixed gear 45 with sufiicient clearance to permit rotation therein.

The output shaft 47 of 48 which, by means of chain 49, is connected to the sprocket 38 of roll 28. The output shaft 50 of gear box 40, carries a sprocket Si which isconnected to sprocket 37 of roll 29, by a chain 52. Thus, upon rotation of the unit 15 by drive sprocket 25, the head i7 and planetary gears 42 and 44 turn about the fixed gear 45, which causes the rotation of the planetary gears in opposite directions. Through the respective trains of gears, sprockets and chains, the feed rolls 28 and' 29 are caused to rotate in opposite direction, and to advance the tube T, which is gripped between the peripheries of the opposed feed rolls.

It will be understood that in order to vary the rate of feed of the tube T, through the wrapping mechanism, so as to correspondingly vary the number of fins per inch to be applied to the tube, the sprocket ratio of the gear boxes and feeding rolls may be adjusted.

The fin flattening and Wrapping unit is generally indicated by the numeral 53, and as shown in Figure 5, consists of a series of swedging and guiding sheaves 54, 55, 56 and 57, fixed on an annular supporting plate 58 andV arranged about the axis of the advancing tube T, so as to lie in progressively advancing vertical planes, or in a spiral path directly related to the advance of the tube. and arranged coaxially with the tube advancing and rotating unit 15 and disposed adjacent the discharge end thereof, so as to receive the advancing tube.

Each of the sheaves 54-57 consists of a pair of opposed flanges, the outer peripheries of which diverge to l accommodate the pre-crimped edge 59 of the strip S, fed from the crimping mechanism (not shown). For purposes of illustration, we will refer to the first sheave 54, Figure 6, where it will be seen that the flanges are rotatably mounted on a short axle 54B and adjacent their peripheries, the ange diverge to form an annular mouth 54A. As seen in Figures 5 and 7, the axle of the flanges 54A is supported in a yoke 6ft which in turn is mounted on a shaft 60A, supported for both longitudinal and rotary adjustment in a bracket 6l, secured to the annular plate 58 by bolts 62. A set screw 63 in the bracket 6l, maintains the proper adjustment of the shaft 69A.

Each of the sheaves 55, 56 and 57 is mounted in the same manner as that just described in connection with sheave 54 and as shown in Figure 7, the individual sheaves are adapted for longitudinal shifting on their respective axes, to adjust their spiral relationship with the adjacent sheaves. This adjustment may be maintained by suitable lock nuts, as shown.

Asdiagrammatically shownv in Figure 6, the flanges of respective sheaves are spaced in progressively closer relation, starting with the first sheave 54Y and ending with the final sheave '7, so that as the crimped strip S advances from feedingA tube 64, in a spiral direction from one sheave to tbe other, its upper crimped edge 65 is received between the opposed parallel surfaces of the flanges of each sheave, with its lower crimped edge lying in the diverging mouths of the respective sheaves. The progressively reduced spacing of the flanges of successive sheaves, thus correspondingly flattens or swedges the upper edge 65 of the strip and simultaneously directs it in a helical course around the tube T. The mouth 57C of the final sheave 57, is of a shape and dimension to leave the desired area and shape of a base crimp .59' on tbe inside or lower edge of the strip, as shown in Figure 9;

The feeding sleevel 64 is secured to the annular supporting plate 58 by any suitable means and directs the crimped strip over the top of the periphery of they tube T, to the space between` the flanges of the first swedging gear box 39, carries a sprocket The annular' plate 58 is supported on a base 58A Car and guiding sheave 54, as will be seen from Figure S.

Any suitable soldering means may be employed in connection with the wrapping unit, to firmly tix the base crimps 59 of the strip S, to the tube T.

In operation, the mechanism just described is conveniently located adjacent the fin-crimping and conditioning machine of said copending application, the precrimped strip S being fed from said machine through guide tube 64 onto the periphery of the tube T. At the outset, a portion of the fin is secured along its base crimp, to the tube T which is longitudinally embraced in the hollow shafts 23 and 24, located at opposite ends of the tube-rotating and advancing unit 15.

When the source of power 27 is set into operation, the sprocket 25, connected to the end plate 16 by means of the hollow shaft 23, causes the entire unit 15 to rotate and as the planetary gears 42 and 44 turn about the fixed gear 45, the feed rolls 28 and 29 are caused to rotate, through the intervening gear boxes 39 and 40. This causes the tube T to be advanced through the auxiliary rollers 32 and 33 and as both sets of rolls are travelling in an annular path about the axis of the tube T in gripping relation with the tube, the tube is rotated at a predetermined speed as it advances through the unit.

As before stated, the flattening and guiding sheaves 54, 55, 56 and 57 are supported on the ring 58 and spaced around the advancing tube in spiral relation thereto, so that the pitch of the spiral is related to the advance of the tube. Thus, the strip S first engages the sheave 54, the flanges of which are spaced apart a greater distance than the flanges of the subsequent sheaves. The sheave 54 receives the strip with its base crimped edge S9 lying in the flaring mouth 54C so as to be unaffected thereby. However, the stretched edge 65 travels between the flanges 54A, the spacing of which is such as to start the flattening of the strip along that edge. As successive sheaves are encountered by the strip the edge 65 is progressively flattened while it is being heli'cally directed onto-the tube T and when the final sheave 57 is reached, the outer edge 65 of the fin has been iompletely flattened.

The initial end of the strip S having been fastened to the tube T, the rotation of the tube actually draws the strip onto the periphery of the tube and through the flattening sheaves just described.

It will be understood that through the medium of the adjustable brackets and the yokes 60, the relationship of the sheaves can be adjusted to assist in determining the pitch of the helical fin. The speed of rotation and advance of the tube may be controlled by varying the ratio of the gear systems and sprockets. Thus, by changing the sprocket ratio, the pitch of the fin may be varied as desired, the speed of tubes advance being the primary factor in determining the pitch of the fin.

From the foregoing, it is believed that my invention may be readily understood without further description, it being borne in mind that numerous changes may be made in the details of construction without departing from the spirit of the invention as set forth in the following claim.

I claim:

In a machine for wrapping fin strip on a heat exchanger tube, mechanism for simultaneously rotating and longitudinally advancing a tube being wrapped, comprising a pair of spaced vertical supports, tube receiving cylinders rotatably mounted coaxially on respective supports, end plates fixed to the opposed' ends of said cylinders between said supports, said end plates being rigidly connected by a pair of roller supporting frames mounted respectively on opposite sides of the axis of said' cylinders, feed rolls rotatably mounted on respective frames with their peripheries in opposed relation to receive a portion of said tube therebetween, means for flexing opposed frames toward one another to adjust the frictional engagement of said rolls with said tube, means for rotatingy said end platesV and frames as a unit, about the axis of said cylinders, and means operable by the rotation of opposite directions.

said unit, for positively rotating the respective feed rolls in References Cited in the le of this patent UNITED STATES PATENTS Gammeter Apr. 22, 1919 Horvath -..0st, 30, 1923 Zimmerman Ian. 19, 1926 10 Dorndorf Sept. 9, 1930 Horvath -Jan. 12, 1932 6 Pickhard Oct. 25, 1932 Mickelson July 21, 1936 Lear ..-Man 28, 1939 Platt Apr. 25, 1944 Stikeleather Apr. 17, 1945 Lear Sept. 24, 1946 Connor Oct. 21, 1947 Schryber Ian. 23, 1951 FOREIGN PATENTS Germany June 30, 1920 Germany Mar. 22, 1938 

